Excavator



'July 7, 1936. H D 2,046,874

EXCAVATOR Filed May 29, 1934 Patented July 7, 1936 UNITED STATES PATENTOFFICE EXCAVA'I'OR Charles N. Hudson, Bremerton, Wash.

Application May 29, 1934, Serial No. 728,11!

1 Claim.-

. ment, a more eflicient means for performing this kind of work than isnow used; and by which a gain of 80 to 90 per cent is efiected under anyand all conditions.

The return of the empty dipper from the point of discharge to thebeginning point of. the next ensuing cut requires more than half thetotal time of operation: Therefore the following specifications andprovided drawing show an excavator designed to profitably utilize thatpart of the provided power which is now dormant during the timenecessary for the return of the dipper from the point of discharge tothe point of cut; and to the end that said dormant power shall beeifectively employed during said interim.

To gain my desired objective I replace the single dipper with twodippers, each having the full capacity of the said single dipper, andthen provide means by whichboth dippers are actuated, alternately, by asingle unit hoisting gear connected with the original power plant. Theresult of such arrangement is the excavation of twice the amountofyardage, with the same power and within the same time required for theoperation of the single dipper.

The mechanical provisions and connections to enable this proposedeconomy in excavation are clearly shown in the accompanying drawing,wherein Fig. 1 shows a side elevation of the tram, articulated with therear end of a suitable frame provided to support it; Fig. 2 is a planview of the same tram and the two leads, M and N, which comprise it;Fig. 3 shows the dipper in perspective; Fig. 4 shows the hoisting drumand connections; Fig. 5 shows cross section of the dipper; Fig. 6 showsside elevation of one of the four temporary inserts to be used toextend. both leads of the tram, if and when required; and Fig. 7 shows adetail of the operating mechanism.

The primal feature of this invention is the tram with its twoconstituent leads M and N swinging freely upon supporting shaft X,mounted on the frame of the dredge. A plate P, Fig. 1, holds each arc,or curve, forming the ends of the leads in rigid position and providesfor the attachment upon shaft X as shown in Fig. 1. The

are the guides traversed by the dipper rollers R, shown in crosssection, Fig. 5.

To fabricate a side member of a lead, two pieces of stock-length angleiron are butted together, as at W, Fig. 1, and held together by a boltedplate, not shown. An are is turned upon each end of I beams AA, one ofwhich has greater diameter than the other, and a latticed superstructureE, for rigidity, is fabricated therewith in conformity with theconventional methods employed in construction of booms and derricks, asshown in Fig. 1.

To fabricate a lead, two side members, fully completed with curved beamsand superstructure, are placed parallel, approximately two feet apart,and securely tied together by transverse plates, indicated by El, Fig.2.

Each lead carries a'dipper comprised of four parts, the head, the shell,the door, and the bail, shown in Figs. 3 and 5. The head is comparableto a. short section of structural channel steel, wide enough betweenflanges to encompass both guides of the lead and with flanges.highenough to cover the guides. Two rollers R, rotative upon andsupported by shouldered gudgeon pins, set

through the flanges, with threaded ends projecting outwardly, areattached to the innerside of each flange and traverse the outwardlyfacing channels of the I beams. The shell D3 is formed of a single pieceof heavy sheet steel with' right angle sides. Vertical slots are cut inthe upper edges of each side to permit adjustment to the projectinggudgeon pins. Two additional'bolts through the shell and flange oneachside hold. the shell firmly to the outer sides of the head flanges.Several flat bars of steel, called shoes, are securely riveted to theunder side of the bottom and extend a few inches beyond the cutting edgeof the shell. These front ends may be sharp and used for cutting butpreferablythey are used for bases to support short teeth of hard steelwhich may be inexpensively replaced or removed and sharpened'when worn.The door, carrying latch D5, is hingedly mounted on the upper rear endof the bucket. The bail is pivotally connected to the sides of thebucket. The draft rod is attached in the conventional manner, but at apoint midway of the width of the head. At the rear end immediately overand above the hinge rod of the door, is attached an adequate spiralspring S, Figs. 1 and 2.

' The tail line B traverses both anchor sheaves C3 and is connected byspiral springs S to the. rear end of each dipper. It is of vitalnecessity in preserving tautness of the head lines B to insure windingand unwinding of the said cables around the drum barrel. The alternatewrap and unwrap of the head line cables around the drum barrel causesthe dippers to ascend or descend their respective leads in likealternating manner, and any looping of either cable, otherwise possible,is prevented by the constant tension exerted by the tail line throughits connection with the rear end of each dipper.

The hoisting mechanism located upon the deck of the pilot housecomprises a single drum of such diameter and length as to accomodate thehead line cables of dippers D and DI in fair alignment and with but asingle layer of cable wrap for each, as shown in Fig. 4.

Main gear F is attached to the end of the shaft supporting said drum andathwart the face of this gear F is located the power shaft F6 to whichis securely attached two pinions Fl at such distance apart that, whenthey are in neutral position with connected lever F2 vertical, each isclear of engagement with main gear F, as in Fig. 1.

The gear by which power is transmitted to shaft F6 is designated by F3,and may be either cog or sprocket with a keyway cut in the hub. It isheld in alignment with its driving member by two substantial bearings.Shaft F6, fitted with a feather key for sliding in the keying of thesprocket, is shifted longitudinally back and forth as pinions Fl aremeshed alternately with gear F. The mesh lever F2 is pivoted to theframe and may control the shifting of the shaft by a yoke operating in acollar; It is obvious that the release of either pinion enmeshed withmain gear F must per force bring said lever into the vertical positionshown and that to mesh the opposite pinion the said lever must befurther advanced by the operator. Thus all engagements of gears are madeby use of mesh lever F2. All releases are automatically produced bydippers contacting trip lever H which, through link F4 and bell crank Flsecured on shaft FII operating a yoke in another collar fixed on theshaft, moves the shaft F6 sufiiciently to release the enmeshed pinionand bring mesh lever F2 into vertical position. The hoisting drumremains motionless until the operator manipulates lever F2 to enmesh thedesired pinion with main gear F.

In the automatic stopping of the hoist, shaft F8 must be shifted in onedirection by one dipper and in the opposite direction by the otherdipper. Figure '7 illustrates the mechanism used for stopping the hoistby the dipper on the far 7 side of Fig. 1. Tripping lever H for thatdipper ,FIII will produce a clockwise movement of shaft FII and thence aforward shifting of shaft F6 to stop the hoist.

Lever F2 can not be moved, inadvertently, in the wrong direction,because dipper D is still in contact with trip lever H until said leverF2 is thrown to mesh the opposite pinion. As shown in the drawing thetop of said lever can not be moved in a direction toward main gear F,but can and must be moved in the opposite direction.

A double ratchet drum Y, Fig. 1, is located in the pilot house at apoint most convenient to the operator's hand. The extremity of each leadM and N, Fig. 2, is connected with drum Y by its respective suspensioncable B2, by means of which the point of either lead may be raised orlowered at will. Vertical flexibility and independent action of theleadsis both desirable and necessary in avoiding boulders, dredging channels,and in meeting various emergencies encountered in excavating placergravel or cleaning bed rock. The double ratchet drum Y is geared to beeasily operable by hand with the tram in horizontal position; and stillmore easily manipulated at an inclination of about forty five degrees,which is the degree of cutting slope generally maintained by excavators.With the tram leads working at the said inclination of forty fivedegrees the dead weight of the ends of the leads is about adequate for aproper feed of the dippers into the face of the cut, requiring handmanipulation to very little extent except in avoiding large boulders.

The installation and adjustment of the dippers to their respective leadsand completion of the necessary cable connections will now beconsidered. Dipper DI is first placed in an inverted position upon thepoint of lead N and advanced until the rollers R are fully enteredwithin the guides whereupon it is temporarily secured. Dipper D isplaced in a likewise inverted position upon the extremity of lead M withits rollers R, likewise entered into the guides. This dipper D is nowpushed downward around the curve, onward and upward until the point ofautomatic discharge is reached, shown at 3, where it is also temporarilysecured until the attachment of its headline with the hoisting drum hasbeen made. The head-line attached to the bail of dipper DI is now passeddownward and around the curve at the extremity of lead N, thencecentrally upward beneath said lead N to its respective connection withthe hoisting drum. While the dippers still occupy these relativepositions, one at the point of discharge upon lead M and the other atthe extremity of lead N, the tail line BI is connected to the rear endof each dipper with spiral springs'S.

First one end of the said tail line BI is attached to the spiral spring8 which in turn is attached to the rear end of dipper head DI From thisconnection the said tail line leads centrally upward over the surface oflead N to and around the anchor sheaves C3, thence downward centrallyover the surface of lead Mto and around the extremity of said lead M,thence centrally upward along the under side of said lead to theconnection with spiral spring 8, attached to the rear end 'of dipperhead D.

Thus with the tram swinging upon the shaft X, located centrally throughthe centers of the curves at its head end, with the extremity of eachlead supported by its respective suspension cable B2 and with all cableconnections of the dippers completed, the relative and alternate actionof the dippers may now be visualized by the manual rotation, back andforth, of main gear F as it functions in the winding and imwinding ofheadlines.

By rotating main gear F in contraclockwise direction the head-lineconnected to dipper DI winds up while simultaneously the head-lineconnected with dipper D unwinds at the same identical speed; and becauseD gives way fully as rapidly as DI can take it there is no more pullexerted upon the head-line of dipper DI than necessary to cut and fill.Exactly the same condition obtains when dipper D is making the alternatecut and fill under lead M with dipper DI descending lead Ii. Withcontinued contraclockwise rotation of dipper DI, with its burden ofgravel, will contact trip lever H, release its load in chute H2 bycontact of latch DI with the edge of the chute, disconnect its hoistingpinion Fl from main gear F and stop further motion of the hoisting drum.With clockwise rotation of main gear F, dipper D will be drawnupwardwhile dipper DI descends, and will contact trip lever H, discharge itscontents into the chute H2, release its hoisting pinion FI and bring thehoisting drum to a full stop, exactly as dipper DI performed. Lever F2must be operated by hand, following the contact of either dipper withtrip lever H to again start the hoist.

The spiral springs SS, shown attached to the rear end of each dipper andtraversing around anchor sheaves, as described, are obviously for thepreservation of tautness throughout the entire connection. Therefore,the vertical gudgeon pins, upon which the sheaves rotate, are rigidlyset in adjustable slotted plates, (not shown), by means of which thetension of the said springs may be renewed whenever any slacknessdevelops. These anchor sheavesare located and attached to thelongitudinal top plates of the superstructure of each lead, immediatelyover and above shaft X, as being the point causing minimum torsion onthe tail line due to the independent raising and lowering of theextremities of the leads.

The curves, or arcs, at either end of each lead should be at least fullhalf circles, and the purposes of each are as follows. Those at thelower extremities of the leads enable the complete inversion of thedippers, which provides more reliable latching of the door without theuse of cumbrous counterbalances and gives to the dippers a sweepingmotion over the bed rock prior to beginning each cut and fill.

when an up-drawn dipper begins traverse of this curve it is thereafterequi-distant from the center of the curve at any point of the peripheryand enables the establishment of a constant point for discharge. withthe dipper held in suspension by its head-line, it is apparent that theextremity of the tram may be raised or low- 5 I ered to any pointbetween vertical and horizontal without in any way affecting the dipperor the said constant point with which the dipper is in contact:Therefore, regardless of tram inclination, the same point of dischargeis always avail- 1o able.

Guiding sheaves may be placed centrally-between the curves at each endof each lead to support the cables around the curves and eliminatefriction, but preferably a number of small 15 rollers, fitted insuitable bearings, at close intervals, are placed transversely acrosseach lead around the curves at each end, for accomplishing the samepurpose, shown at RI.

Manifestly, in its operation, the frame to which 20 my excavator isattached rests upon the ground to be excavated and is moved forwardintermittently as the excavation progresses: 1 thus preserving thedesired slope of cut and inclination of tram. The arrangement of theindependent 25 leads provides means for avoiding boulders until they aretaken from the face of the slope and removed from further interference.

Obviously, changes may be made in the form, dimensions and arrangementof my invention 30 without departing fromthe spirit thereof.

What I claim is:

In a dredging apparatus, the combination of a pair of leads mounted onthe dredger for vertical swinging movement independently or to- 35gether, each of the leads carrying a scoop mounted for reciprocatorymovement along the lead, means for reciprocating the scoops and meansfor connecting the scoops so that they operate alternately in performingtheir digging operation. 40

CHARLES N. HUDSON.

